Let's say you were a pre-operative male-to-female transsexual. Don't you think that a week before your operation, you'd find out that you had an 18-year-old son who was in jail on the other side of the country, and that your therapist wouldn't let you go ahead with the surgery unless you flew out there, bought a car and then drove across America having wacky adventures with the boy, all the time wondering if he'll figure out that you're really his father?

I mean, you might think all that if you were living in a sitcom. Which is to say that Transamerica has an enormous plot flaw, the kind of thing that turns a bad episode of Happy Days into a catch phrase. But once you get over this, it turns out to be a decent film, with a more-than-decent performance by Felicity Huffman.

Huffman plays the M2F, and it's a freakishly good act. In spite of the fact that I'm pretty sure Felicity Huffman was born a woman, her character really seems to be more of a man, especially when she tries to act female. It's sort of like if you were to watch George Bush try to act stupid, and he came off as smart.

Huffman's performance is so immersive that she got an Oscar nomination for this role, and she stands a good chance of getting the actual award. Which is surprising, because Transamerica is actually a decent film and not just a grubby ploy to get a prize by having the lead character be gay, developmentally disabled or ugly.

Once the ridiculous plot gets rolling, it becomes something of a paean to the road movies of the '60s and '70s. It's littered with little clichés, like the meeting with the noble Native American man (Graham Greene), the romantic encounter at the truck stop, picking up the groovy hitchhiker who dispenses wisdom and steals wallets, and I think there's a scene where Billy and Captain America get their genitals surgically altered while taking acid in New Orleans.

Somehow, though, these time-worn bits only enhance the movie. It's not just that Huffman is so fun to watch in the role of Bree; it's that writer Duncan Tucker, in spite of his inability to come up with original story elements, is gifted at crafting dialogue.

The best scenes involve Bree's encounter with her long-estranged mother, father and sister. In what must be the most perfect of hells for a young person with gender-identity issues, Bree was raised in the scorched suburbs of Phoenix.

Burt Young and Fionnula Flanagan play her father and mother, who don't quite know how to deal with their son Stanley's new breasts. "Your mother and I both love you," says her dad. "But we don't respect you," adds her mom.

Young and Flanagan are like an old vaudeville act in these parts, taking bits and pieces from a dozen other mother/father pairs. Young plays the classic hen-pecked dad: He's a guy who doesn't have a lot of opinions and doesn't understand why his wife has so many. Flanagan does a kind of whiteified version of Nancy Walker's Ida Morgenstern character as the buttinski mom. It's a deeply horrifying performance, the kind of acting that realistically captures those unreal people whose hair forms a protective heat-shield around their head and whose lady-suits have been cryogenically frozen in fashion since 1984.

Kevin Zegers is also good as Bree's unknowing son, Toby. He has a sleazy sexuality that plays out well against Huffman's incredible uptightness. While Bree feels uncomfortable being seen in a heavy bathrobe, Toby freely flings off his clothing anytime he feels there's a good opportunity for displaying his nipples.

The only miscue in the acting is Elizabeth Peña as Bree's psychotherapist, but it's such a ridiculous role that it's hard to imagine anyone pulling it off. Peña has to seem kind and caring, and at the same time demand that Bree perform a series of arbitrary and Herculean tasks before allowing her to get some dangle-flesh trimmed.

It's clear, though, that this film belongs to Huffman. She's sure to get a lot of accolades, but I bet she'll also inspire a series of cookie-cutter articles from the middle-brow culture critics of the pseudo-right, whose talking points now include mentioning the "gay agenda" every time a cowgirl gets her Red Wings.

They're sure to claim that a sympathetic film about a pre-operative transsexual is just a ploy to further the homoification of our otherwise supremely penile-vaginal country, and that the left-wing sapphists and nancy-boys who run Hollywood are rubbing our faces in their awful otherness by awarding the dildo-esque Oscar statue to the statuesque Ms. Huffman. Actually, I hope the half-wits do write that, because Transamerica is a very tiny film, and that might be just the publicity it needs to reach what, with its sitcom plotting and heart-warming zaniness, is its natural audience: the good people of hometown America.